﻿#ifdef _WIN32
#include "strptime_win.h"
#include <ctime>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cctype>

#define TM_YEAR_BASE 1900

/*
 * We do not implement alternate representations. However, we always
 * check whether a given modifier is allowed for a certain conversion.
 */
#define ALT_E     0x01
#define ALT_O     0x02
#define LEGAL_ALT(x)    { if (alt_format & ~(x)) return (0); }

static int conv_num(const char**, int*, int, int);

static const char* day[7] = {
		"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
		"Friday", "Saturday"
};
static const char* abday[7] = {
		"Sun","Mon","Tue","Wed","Thu","Fri","Sat"
};
static const char* mon[12] = {
		"January", "February", "March", "April", "May", "June", "July",
		"August", "September", "October", "November", "December"
};
static const char* abmon[12] = {
		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char* am_pm[2] = {
		"AM", "PM"
};


//window上自己实现strptime函数，linux已经提供strptime
//strptime函数windows平台上实现
char*
strptime(const char* buf, const char* fmt, struct tm* tm)
{
	char c;
	const char* bp;
	size_t len = 0;
	int alt_format, i, split_year = 0;

	bp = buf;

	while ((c = *fmt) != '\0')
	{
		/* Clear `alternate' modifier prior to new conversion. */
		alt_format = 0;

		/* Eat up white-space. */
		if (isspace(c))
		{
			while (isspace(*bp))
				bp++;

			fmt++;
			continue;
		}

		if ((c = *fmt++) != '%')
			goto literal;


	again:    switch (c = *fmt++)
	{
	case '%': /* "%%" is converted to "%". */
		literal :
			if (c != *bp++)
				return (0);
		break;

		/*
		 * "Alternative" modifiers. Just set the appropriate flag
		 * and start over again.
		 */
	case 'E': /* "%E?" alternative conversion modifier. */
		LEGAL_ALT(0);
		alt_format |= ALT_E;
		goto again;

	case 'O': /* "%O?" alternative conversion modifier. */
		LEGAL_ALT(0);
		alt_format |= ALT_O;
		goto again;

		/*
		 * "Complex" conversion rules, implemented through recursion.
		 */
	case 'c': /* Date and time, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%x %X", tm)))
			return (0);
		break;

	case 'D': /* The date as "%m/%d/%y". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%m/%d/%y", tm)))
			return (0);
		break;

	case 'R': /* The time as "%H:%M". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%H:%M", tm)))
			return (0);
		break;

	case 'r': /* The time in 12-hour clock representation. */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%I:%M:%S %p", tm)))
			return (0);
		break;

	case 'T': /* The time as "%H:%M:%S". */
		LEGAL_ALT(0);
		if (!(bp = strptime(bp, "%H:%M:%S", tm)))
			return (0);
		break;

	case 'X': /* The time, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%H:%M:%S", tm)))
			return (0);
		break;

	case 'x': /* The date, using the locale's format. */
		LEGAL_ALT(ALT_E);
		if (!(bp = strptime(bp, "%m/%d/%y", tm)))
			return (0);
		break;

		/*
		 * "Elementary" conversion rules.
		 */
	case 'A': /* The day of week, using the locale's form. */
	case 'a':
		LEGAL_ALT(0);
		for (i = 0; i < 7; i++)
		{
			/* Full name. */
			len = strlen(day[i]);
			if (strncmp(day[i], bp, len) == 0)
				break;

			/* Abbreviated name. */
			len = strlen(abday[i]);
			if (strncmp(abday[i], bp, len) == 0)
				break;
		}

		/* Nothing matched. */
		if (i == 7)
			return (0);

		tm->tm_wday = i;
		bp += len;
		break;

	case 'B': /* The month, using the locale's form. */
	case 'b':
	case 'h':
		LEGAL_ALT(0);
		for (i = 0; i < 12; i++)
		{
			/* Full name. */
			len = strlen(mon[i]);
			if (strncmp(mon[i], bp, len) == 0)
				break;

			/* Abbreviated name. */
			len = strlen(abmon[i]);
			if (strncmp(abmon[i], bp, len) == 0)
				break;
		}

		/* Nothing matched. */
		if (i == 12)
			return (0);

		tm->tm_mon = i;
		bp += len;
		break;

	case 'C': /* The century number. */
		LEGAL_ALT(ALT_E);
		if (!(conv_num(&bp, &i, 0, 99)))
			return (0);

		if (split_year)
		{
			tm->tm_year = (tm->tm_year % 100) + (i * 100);
		}
		else
		{
			tm->tm_year = i * 100;
			split_year = 1;
		}
		break;

	case 'd': /* The day of month. */
	case 'e':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
			return (0);
		break;

	case 'k': /* The hour (24-hour clock representation). */
		LEGAL_ALT(0);
		/* FALLTHROUGH */
	case 'H':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
			return (0);
		break;

	case 'l': /* The hour (12-hour clock representation). */
		LEGAL_ALT(0);
		/* FALLTHROUGH */
	case 'I':
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
			return (0);
		if (tm->tm_hour == 12)
			tm->tm_hour = 0;
		break;

	case 'j': /* The day of year. */
		LEGAL_ALT(0);
		if (!(conv_num(&bp, &i, 1, 366)))
			return (0);
		tm->tm_yday = i - 1;
		break;

	case 'M': /* The minute. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
			return (0);
		break;

	case 'm': /* The month. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &i, 1, 12)))
			return (0);
		tm->tm_mon = i - 1;
		break;

	case 'p': /* The locale's equivalent of AM/PM. */
		LEGAL_ALT(0);
		/* AM? */
		if (strcmp(am_pm[0], bp) == 0)
		{
			if (tm->tm_hour > 11)
				return (0);

			bp += strlen(am_pm[0]);
			break;
		}
		/* PM? */
		else if (strcmp(am_pm[1], bp) == 0)
		{
			if (tm->tm_hour > 11)
				return (0);

			tm->tm_hour += 12;
			bp += strlen(am_pm[1]);
			break;
		}

		/* Nothing matched. */
		return (0);

	case 'S': /* The seconds. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
			return (0);
		break;

	case 'U': /* The week of year, beginning on sunday. */
	case 'W': /* The week of year, beginning on monday. */
		LEGAL_ALT(ALT_O);
		/*
		 * XXX This is bogus, as we can not assume any valid
		 * information present in the tm structure at this
		 * point to calculate a real value, so just check the
		 * range for now.
		 */
		if (!(conv_num(&bp, &i, 0, 53)))
			return (0);
		break;

	case 'w': /* The day of week, beginning on sunday. */
		LEGAL_ALT(ALT_O);
		if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
			return (0);
		break;

	case 'Y': /* The year. */
		LEGAL_ALT(ALT_E);
		if (!(conv_num(&bp, &i, 0, 9999)))
			return (0);

		tm->tm_year = i - TM_YEAR_BASE;
		break;

	case 'y': /* The year within 100 years of the epoch. */
		LEGAL_ALT(ALT_E | ALT_O);
		if (!(conv_num(&bp, &i, 0, 99)))
			return (0);

		if (split_year)
		{
			tm->tm_year = ((tm->tm_year / 100) * 100) + i;
			break;
		}
		split_year = 1;
		if (i <= 68)
			tm->tm_year = i + 2000 - TM_YEAR_BASE;
		else
			tm->tm_year = i + 1900 - TM_YEAR_BASE;
		break;

		/*
		 * Miscellaneous conversions.
		 */
	case 'n': /* Any kind of white-space. */
	case 't':
		LEGAL_ALT(0);
		while (isspace(*bp))
			bp++;
		break;


	default:  /* Unknown/unsupported conversion. */
		return (0);
	}


	}

	/* LINTED functional specification */
	return ((char*)bp);
}


static int conv_num(const char** buf, int* dest, int llim, int ulim)
{
	int result = 0;

	/* The limit also determines the number of valid digits. */
	int rulim = ulim;

	if (**buf < '0' || **buf > '9')
		return (0);

	do
	{
		result *= 10;
		result += *(*buf)++ - '0';
		rulim /= 10;
	} while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');

	if (result < llim || result > ulim)
		return (0);

	*dest = result;
	return (1);
}

#endif
